Mixtures of monoazo dyes: dicyano-nitrobenzene azo compounds

ABSTRACT

The invention relates to mixtures of monoazo dyes, which are characterized in that they consist of one or more dyes of the general formula I   &lt;IMAGE&gt; (I)  and one or more dyes of the general formula II   &lt;IMAGE&gt; (II)  where R1 is methyl, ethyl, n-propyl or i-propyl, R2 is ethyl or n-propyl, m is 2 or 3 and n is 1 or 2, with the proviso that m+n is 4, processes for preparing same and the use thereof for dyeing and printing hydrophobic fibre materials and blends thereof with natural fibre materials.

The invention relates to mixtures of monoazo dyes, which arecharacterised in that they contain one or more dyes of the generalformula I ##STR3## and one or more dyes of the general formula II##STR4## where R¹ is methyl, ethyl, n-propyl or i-propyl,

R² is ethyl or n-propyl,

m is 2 or 3 and

n is 1 or 2, with the proviso that m+n is 4.

The invention also relates to processes for preparing the dye mixturesof the present invention and to the use thereof for dyeing and printinghydrophobic fibre materials and their blends with natural fibrematerials.

Mixtures similar to the mixtures of the present invention are alreadyknown and described for example in GB-2,108,141.

It has now been found, surprisingly, that the mixtures of the presentinvention have significantly improved dyeing properties compared withthe individual dyes and compared with the mixtures of GB-2,108,141.

The dye mixtures of the present invention consist of one or more dyes ofthe general formula I and one or more dyes of the general formula II.Preference is given to dye mixtures of the present invention whichcontain one or two dyes of the general formula I and a single dye of thegeneral formula II.

Preference is given to mixtures which contain dyes of the generalformula I where R¹ is methyl or ethyl or in particular n-propyl and R²is ethyl. Preferred mixtures also include those which contain only twodyes of the general formula I and one dye of the general formula IIwhere R¹ denotes methyl in one and n-propyl in the other and R² denotesethyl in both dyestuffs of the formula I or where R¹ denotes methyl inboth and R² ethyl in one and n-propyl in the other dyestuff of theFormula I.

In the dye mixtures of the present invention, the ratio of the variousdyes of the general formulae I and II can vary within relatively widelimits. In general, the minimum weight proportion of one component is10% and the maximum proportion is 90%. by weight based on the totalweight of the dye components wherein the total weight proportions of alldye components is 100%. In dye mixtures which contain only one dye eachof the general formulae I and II, the mixing ratio is preferably withinthe range from 70/30 to 30/70; that is, the weight proportion of a dyeis from 30 to 70% by weight based on the total weight of the dyecomponents.

The individual dyes of the general formulae I and II are known anddescribed for example in DE Patent 1,794,402, EP-36,512 and JapanesePatent Application JP-63,189,465.

The dye mixtures of the present invention can be prepared by variousmethods, for example by mixing the separately prepared and separatelyfinished individual dyes. This mixing process is effected in suitablemixers, for example tumble mixers, or in suitable mills, for exampleball and sand mills. However, separately finished individual dyes canalso be mixed by stirring into dyeing liquors.

Preferably, the mixtures of the present invention are obtained byconjoint finishing of the separately prepared individual components.

This conjoint finishing is characterised in that a dye mixture of atleast one dye each of the general formulae I and II is milled in thepresence of dispersants in suitable mills, for example ball or sandmills, and, if a pulverulent dye form is to be prepared, is subsequentlyspray-dried.

Suitable dispersants are for example anionic or nonionic dispersants,which may also be used together. Anionic dispersants are for examplecondensation products of aromatic sulphonic acids and formaldehyde, inparticular condensation products of alkylnaphthalene sulphonic acids andformaldehyde, condensation products of substituted or unsubstitutedphenol with formaldehyde and sodium bisulphite, alkali metal salts ofcondensation products of substituted or unsubstituted phenol,naphthalene- or naphthol-sulphonic acids, formaldehyde and sodiumbisulphite, alkali metal salts of condensation products of substitutedor unsubstituted phenolsulphonic acids, formaldehyde and urea and alsoalkali metal salts of ligninsulphonic acids; alkane- oralkylarene-sulphonates, and also alkylaryl polyglycol ether sulphates.Nonionic dispersants or emulsifiers are for example reaction products ofalkylene oxides, for example ethylene oxide or propylene oxide, withalkylatable compounds, for example fatty alcohols, fatty amines, fattyacids, phenols, alkylphenols, arylalkylphenols, arylalkylarylphenols andcarboxamides, for example addition products of from 5 to 10 ethyleneoxide units with C₈ -C₁₀ -alkylphenols.

The milling takes place at temperatures between 10° and 90° C.,preferably at from 30° to 60° C. In the conjoint finishing of separatelyprepared, individual components, conjoint milling at temperatures above30° C. is advantageous. In the course of milling, the dye particles aremechanically comminuted to such an extent as to obtain an optimumspecific surface area and as to minimise the sedimentation of the dye.The particle size of the dyes lies in general between 0.5 and 5 μm,preferably at about 1 μm.

It is advantageous to subject the separately prepared individualcomponents of the dye mixture to a conjoint thermal treatment before theconjoint milling. This thermal treatment is characterised in that theindividual components of the dye mixture are heated under atmospheric orsuperatmospheric pressure in water for half an hour to several hours atfrom 50° to 150° C., preferably at from 90° to 130° C., and cooled backdown again. This heating advantageously takes place in the presence ofone or more dispersants or an organic solvent. Such solvents are forexample methanol, ethanol, dimethylformamide or dimethyl sulphoxide, butpreferably only sparingly water-soluble solvents such as toluene,chlorobenzene, 1,2-dichlorobenzene or butyl acetate. These solvents aredistilled off again after the thermal treatment.

A preferred pretreatment of the individual components of the dye mixtureprior to the conjoint milling is the conjoint dissolving of theindividual components in an organic solvent or solvent mixture withsubsequent crystallisation or precipitation, and isolation, for exampleby filtration and removal of solvent residues, for example by washing.

The dye dispersions thus obtained can be used with great advantage formaking up print pastes and dyeing liquors. They offer particularadvantages for example in continuous processes where the dyeconcentration of the dyeing liquors must be kept constant by continuousfeeding of dye into the running apparatus.

Powder formulations are preferred for certain applications. Thesepowders contain the dye, dispersant and other auxiliaries, for examplewetting, oxidising, preserving and dustproofing agents.

A preferred method of preparing pulverulent dye preparations consists inremoving the liquid from the above-described liquid dye dispersions, forexample by vacuum drying, freeze drying, by drying on drum dryers, butpreferably by spray drying.

The dye contents of the liquid dye formulations range from 20 to 40%,and the dispersant contents from about 20 to 40%. In the case of powderformulations the dye contents range from 20 to 60% and the dispersantcontents from 40 to 80%. For economic reasons the dye content is usuallynot less than 20%.

The dye mixtures of the present invention as such or else mixed withother disperse dyes are highly suitable for dyeing and printinghydrophobic synthetic fibre materials and blends thereof with naturalfibre materials. Surprisingly, they are superior to the individual dyesin respect of dyeing properties and colouristic fastness properties, forexample thermomigration, fastness to dry heat setting and pleating,water, washing and rub fastness, in particular in build-up andexhaustion properties and in levelling power. Moreover, the dye mixturesof the present invention still give very strong dyeings with excellentbath exhaustion even if the dyeing temperatures are lowered and thedyeing time is shortened.

Suitable hydrophobic synthetic materials are for example cellulose-2,5-acetate, cellulose triacetate, polyamides and particularly polyesters,for example polyethylene terephthalate. Blends thereof with naturalfibre materials are for example with cotton, regenerated cellulosefibres or wool.

The invention is further illustrated by the following examples:

EXAMPLE 1

14.7 g of the dye of the formula III ##STR5##

14.7 g of the dye of the formula IV ##STR6## are conjointly homogenisedwith 227.6 g of water, 86.8 g of a higher molecular weightligninsulphonate and 6.3 g of an aryl polyglycol ether using a dissolverdisc and the pH is brought to 8.0 with 2.6 ml of 50% strength aceticacid. This batch is then milled in a water-cooled bead mill to afineness of <5μ, and the mill-base thus obtained is screened to separateoff milling media and then dried with a spray dryer.

1.25 g of the dye thus obtained are dispersed in 2000 g of water. Thedispersion is admixed with 4 g of ammonium sulphate, 2 g of commercialdispersant based on a condensation product of sodiumnaphthalenesulphonate and formaldehyde and 2 g of a condensation productof m-cresol, formaldehyde and sodium sulphite and brought to pH 5.5 withacetic acid. The dyeing liquor thus obtained is entered with 100 g of atextured polyester fabric based on polyethylene terephthalate, which isdyed therein at 125° C. for 1/2 hour. Subsequent rinsing, reductionclearing with 0.2% strength sodium dithionite solution at from 70° to80° C. for 15 minutes, rinsing and drying gives a strong blue dyeinghaving excellent colouristic properties.

If to test the exhaustion the dye bath is subsequently entered with 100g of a textured polyester fabric based on polyethylene terephthalate fora dyeing at 135° C. for 1 hour and the dyeing is subsequently treated inthe same way as the actual dyeing, a virtually colourless dyeing isobtained.

EXAMPLE 2

10 g of the dye of the formula V ##STR7## 5 g of the dye of the formulaVI ##STR8## and 14.4 g of the dye of the formula VII ##STR9## areconverted into a powder preparation and dyed as described in Example 1.Again a strong blue dyeing is obtained with excellent colouristicfastness properties and almost complete bath exhaustion.

EXAMPLE 3

If in Example 1 the 14.7 g of the dye of the formula III are replaced bythe corresponding amount of the dye of the formula V ##STR10## and theprocedure is otherwise as described in Example 1, again a strong bluedyeing is obtained with excellent colouristic properties and an onlyslightly coloured exhaustion test dyeing.

The table below shows further dye mixtures of the present invention withthe meanings for R¹ and R² and m and n and the weight ratio of theindividual dyes, which are preparable as described above and whichlikewise produce strong blue dyeings and prints on polyester materialswith again very good colouristic properties.

                  TABLE                                                           ______________________________________                                                                              Mixing                                  Example   R.sup.1  R.sup.2 m      n   ratio                                   ______________________________________                                         4        C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                       --     --  40                                                --       --      2      2   60                                       5        CH.sub.3 nC.sub.3 H.sub.7                                                                      --     --  65                                                --       --      2      2   35                                       6        C.sub.2 H.sub.5                                                                        nC.sub.3 H.sub.7                                                                      --     --  30                                                --       --      2      2   70                                       7        nC.sub.3 H.sub.7                                                                       nC.sub.3 H.sub.7                                                                      --     --  50                                                --       --      2      2   50                                       8        iC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --   331/3                                            --       --      2      2    662/3                                   9        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --  50                                                --       --      3      1   50                                      10        CH.sub.3 nC.sub.3 H.sub.7                                                                      --     --  20                                                --       --      3      1   80                                      11        C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                       --     --  45                                                --       --      3      1   55                                      12        C.sub.2 H.sub.5                                                                        nC.sub.3 H.sub.7                                                                      --     --  90                                                --       --      3      1   10                                      13        nC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  55                                                --       --      3      1   45                                      14        iC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  35                                                --       --      3      1   65                                      15        iC.sub.3 H.sub.7                                                                       nC.sub.3 H.sub.7                                                                      --     --  25                                                --       --      3      1   75                                      16        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --  25                                                nC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  25                                                --       --      2      2   50                                      17        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --  35                                                nC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  15                                                --       --      2      2   50                                      18        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --  25                                                CH.sub.3 nC.sub.3 H.sub.7                                                                      --     --  25                                                --       --      2      2   50                                      19        CH.sub.3 nC.sub.3 H.sub.7                                                                      --     --  20                                                nC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  40                                                --       --      2      2   40                                      20        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --  35                                                C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                       --     --  40                                                --       --      2      2   25                                      21        C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                       --     --  10                                                nC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  60                                                --       --      2      2   30                                      22        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --   331/3                                            iC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --   331/3                                            --       --      2      2    331/3                                  23        iC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --   5                                                iC.sub.3 H.sub.7                                                                       nC.sub.3 H.sub.7                                                                      --     --  55                                                --       --      2      2   40                                      24        nC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  50                                                iC.sub.3 H.sub.7                                                                       C.sub.2 H.sub. 5                                                                      --     --  10                                                --       --      2      2   40                                      25        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --  25                                                CH.sub.3 nC.sub.3 H.sub.7                                                                      --     --   5                                                nC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  35                                                --       --      2      2   35                                      26        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --  40                                                --       --      2      2   15                                                --       --      3      1   45                                      27        nC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  30                                                --       --      2      2   60                                                --       --      3      1   10                                      28        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --  50                                                --       --      3      1   50                                      29        CH.sub.3 nC.sub.3 H.sub.7                                                                      --     --  70                                                --       --      3      1   30                                      30        C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                       --     --  30                                                --       --      3      1   70                                      31        C.sub.2 H.sub.5                                                                        nC.sub.3 H.sub.7                                                                      --     --  40                                                --       --      3      1   60                                      32        nC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  80                                                --       --      3      1   20                                      33        nC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  50                                                --       --      3      1   50                                      34        iC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  45                                                --       --      3      1   55                                      35        iC.sub.3 H.sub.7                                                                       nC.sub.3 H.sub.7                                                                      --     --  30                                                --       --      3      1   70                                      36        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --  25                                                CH.sub.3 nC.sub.3 H.sub.7                                                                      --     --  25                                                --       --      3      1   50                                      37        CH.sub.3 nC.sub.3 H.sub.7                                                                      --     --  50                                                C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                       --     --  10                                                --       --      3      1   40                                      38        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --   331/3                                            nC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --   331/3                                            --       --      3      1    331/3                                  39        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --  40                                                iC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  45                                                --       --      3      1   15                                      40        CH.sub.3 nC.sub.3 H.sub.7                                                                      --     --  10                                                nC.sub.3 H.sub.7                                                                       C.sub.2 H.sub.5                                                                       --     --  30                                                --       --      3      1   60                                      41        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --  70                                                --       --      3      1   30                                      42        CH.sub.3 C.sub.2 H.sub.5                                                                       --     --  30                                                --       --      3      1   70                                      ______________________________________                                    

We claim:
 1. Mixtures of monoazo dyes comprising one or more dyes of thegeneral formula I ##STR11## and one or more dyes of the general formulaII ##STR12## where R¹ is methyl, ethyl, n-propyl or i-propyl,R² is ethylor n-propyl, m is 2 or 3 and n is 1 or 2, with the proviso that m+n is4.
 2. Dye mixture according to claim 1 comprising one or two dyes eachof the general formulae I and II.
 3. Dye mixture according to claim 1wherein the weight proportion of each dye component is from 10 to 90% byweight based on the total weight of the dye components wherein the totalweight proportions of all the dye components is 100%.
 4. Dye mixtureaccording to claim 3 comprising only one dye each of the generalformulae I and II wherein the weight proportion of the dye components isfrom 30 to 70% by weight based on the total weight of the dyecomponents.
 5. Dye mixtures according to claim 1 containing a dye of thegeneral formula I wherein R¹ is n-propyl.
 6. Dye mixture according toclaim 1 containing a dye of the general formula I wherein R² is ethyl.7. Dye mixture according to claim 1 containing two dyes of the generalformula I and one dye of the general formula II, where R¹ denotes methylin one and n-propyl in the other and R² denotes ethyl in both dyestuffsof the formula I or where R¹ denotes methyl in both and R² ethyl in oneand n-propyl in the other dyestuff of the formula I.
 8. A process fordyeing and printing hydrophobic fibre materials and blends thereof withnatural fibre materials using the dye mixtures of claim 1.